Biology
SIR Epidemic
S'=-βSI · I'=βSI-γI · R'=γI

Susceptible, infected and recovered fractions over an outbreak — the infected curve peaks then burns out. Integrated by the real Medicine.Epidemiology SirModel.
Computed & rendered in pure C# on the frozen OnlyCSharp 1.8 library — animation baked to GIF with the library's own
Gif encoder (no GPU, no ffmpeg, no external packages).